The invention relates to a method for laser-assisted bonding of substrates, in which these are connected together firstly frictionally by pressing together and subsequently strengthening of the connection between the substrates is effected by activation in regions which is induced by laser irradiation. The invention likewise relates to substrates produced accordingly.
Direct bonding or wafer bonding known from the state of the art is based on the principle that surfaces with sufficient planarity can be connected together because of adhesion forces. This direct bonding is effected at temperatures in the range of room temperature up to TG point or up to melting point. Methods of this type are known for example from DE 197 52 412 A1 and DE 100 48 374 A1.
However, at room temperature, direct bonding provides only a weak connection between substrates and normally must be supplemented by subsequent tempering at increased temperatures in order to achieve sufficient adhesion strengths of the joined parts. Therefore normally only at temperatures of above 300° C. can a significant increase in adhesion forces and hence strengthening of the connection be achieved. A substantial disadvantage of the temperature treatment however affects substrates which have a different thermal expansion behaviour.